High frequency arc fault detection

ABSTRACT

A system for identifying an arc fault in a wire, the system comprising a controller operably connected to a first load via first wire; the controller configured to supply a current to the first load, wherein the controller is operable to measure and filter the first voltage on the first wire with a bandpass filter having a selected pass band to select and retain spectral content, amplify the retained spectral content, and identify an envelope of the amplified retained spectral content. The controller also operable to measure a first current in the first wire and correlate changes in the first current with a characteristic of the amplified retained spectral content to identify an arc fault, wherein the characteristic includes a buffered envelope as a signal indicative of the amount of energy in the selected passband frequency range.

BACKGROUND

The present disclosure relates to aircraft controllers and arc faultdetection and, in particular, arc fault detection and protection forsolid state power controller circuits and components on an aircraft.

Vehicles, such as aircraft, typically utilize one or more electroniccontrol unit(s) (ECU) and/or Solid State Power Controllers (SSPC),various sensors, and actuators in various control applications to ensureinflight operation, provide for redundancy, and fail-operationalcapabilities. A primary function performed by an ECU in an aircraftapplication is engine and flight control, while a primary function of anSSPC is power control and distribution. The electronic control and powerdistribution systems, are generally interconnected by long distances ofwiring routed through cable ways and provided behind various sealed walland fuselage panels. Wiring in aircraft can be critical to properoperation and regular checks and maintenance are often essential toensure that wires remain serviceable and in good repair. Damage to thewires can occur due to aging, accidental damage, vibration, chaffing orrubbing against mounts and other wires during flight, bending, gettingwet, oily, contaminated, stamped on, or crushed, and the like.

However, over time and due to varied environmental conditions that wiresand wire harnesses are subjected to can lead to, the wire insulationbecoming more brittle and as a result, arc faults may occur. Arc faultsmay also be particularly difficult to detect and isolate as many arcfaults may be intermittent. Moreover, in some instances, arc faultscould lead to arcing, sparks and the like as possible ignition sourcefor combustible materials.

Given the potential risks and concerns associated with arcing, and arcfaults, various arc detection systems have therefore been developed.However arc fault detectors have been made for detecting series arcs(i.e., wire connection breaks) and for detecting parallel arcs(connections/shorts to ground). Previous arc fault detectors have beenimplemented by looking for changes in the load current or trying tocorrelate noise signals radiated or conducted from a particularload/wire. The accuracy and sensitivity of detection (especially forseries arc fault detection), needs improvement, both to detect validfaults and to avoid nuisance detections and fault indications.

SUMMARY

According to one embodiment, disclosed herein is a method of identifyingan arc fault in a wire operably connected between a controller and aload. The method includes operably connecting a sense wire to the wiresupplied by the controller via the wire, measuring a first voltage onthe wire at the load via the sense wire, measuring a second voltage onthe wire at an output interface of the controller and measuring acurrent in the first wire. The method also includes identifying anydifferences between the voltage on the wire measured at the load and thesecond voltage on the wire measured at the output interface,ascertaining any anomalies in the current measured in the wire, andcorrelating the differences between the first voltage and the secondvoltage with any anomalies in the current to identify an arc fault.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include routing thefirst sense wire in parallel with the first wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that thefirst sense wire is a shield associated with the first wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include routing thesense first wire with another wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include the firstsense wire is connected to the first wire in close proximity to thefirst load.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include operablyconnecting a second sense wire to a second wire connected to a secondload supplied by the controller via the second wire, measuring a thirdvoltage on the second wire at the load via the second sense wire,measuring a fourth voltage on the second wire at a second outputinterface of the controller, and measuring a second current in thesecond wire. The method also further includes identifying anydifferences between the third voltage on the second wire measured at theload and the fourth voltage on the second wire measured at the secondoutput interface, ascertaining any anomalies in the second currentmeasured in the second wire, and correlating the differences between thethird voltage and the fourth voltage with any anomalies in the secondcurrent to identify an arc fault.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include the firstload and the second load are the same.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include routing thefirst sense wire in parallel with the second wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include routing thesecond sense wire with the first wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that thesecond sense wire is connected to the second wire in close proximity tothe second load.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include a third wireand a third sense wire, wherein the load is a three phase load.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that thecorrelating further includes receiving a signal indicative of theenvelope of the spectral content on the wire under test in a selectedfrequency range, receiving the signal indicative of current in the wireunder test based on the measuring, applying a negative clipping functionto the signal to form a positive envelope signal, and applying aderivative function to the positive envelope signal, the derivativefunction yielding a pulse signal indicative of changes in the positiveenvelope signal. If the pulse signal exceeds a first selected threshold,integrating the pulse signal to yield an accumulated pulse signal;otherwise set the accumulated pulse signal to zero. In addition, if theaccumulated pulse signal exceeds a second threshold set a first flag astrue indicating a selected amount of information indicative of an arcfault has been acquired. The method also includes counting theoccurrences the first flag is set as true, if the count exceeds aselected third threshold, set a second flag indicating the that thespectral content as measured from the wire indicates a possible seriesarc fault. The method further includes filtering the signal indicativeof the current in the wire to formulate a pulse associated with when themeasured current exhibits an interruption, and accumulating instanceswhen the measured current exhibits an interruption based on the pulses.If the accumulated instances when the measured current exhibits aninterruption exceeds a fourth selected threshold a second flagindicating the that the spectral contend as measured from the wireindicates a possible series arc faults is set, then identify a seriesarc fault in the wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include thecontroller being further operable to execute a method of identifying anarc fault in a wire further comprising, if the accumulated pulse signalexceeds a fifth selected threshold and the count exceeds a selectedsixth selected threshold, set a third flag indicating the that thespectral content as measured from the wire indicates a possible parallelarc fault, filtering the signal indicative of the current in the wire toformulate pulses associated with when the measured current exhibits aninterruption. If the pulses exceed a seventh selected threshold,accumulating instances when the measured current exhibits aninterruption based on the pulses, if the accumulated instances when themeasured current exhibits an interruption exceeds an eighth selectedthreshold setting a fourth flag indicative of a current fault, if thethird flag indicating the that the spectral content as measured from thewire indicates a possible parallel arc fault is set and the fourth flagindicating a sufficient current fault is set, identify a parallel arcfault for the wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that thereceiving a signal indicative of the envelope of the spectral content onthe wire under test in a selected frequency range is based on filteringthe first voltage on the first wire with a bandpass filter having aselected pass band to select and retain spectral content, wherein thepass band frequency range in the range of about 10 MHz to about 40 MHz,amplifying the retained spectral content with a linear preamplifier, andidentifying an envelope of the amplified retained spectral content byapplying a logarithmic amplifier to the amplified retained spectralcontent, the envelope indicative of the RF energy content of thespectral content in the pass band. The controller includes a currentsense function, the current sense function including measuring a firstcurrent in the first wire. The method also includes correlating changesin the first current with a characteristic of the amplified retainedspectral content to identify an arc fault, wherein the characteristicincludes a buffered envelope as a signal indicative of the amount ofenergy in the selected pass band frequency range.

Also described herein in another embodiment is system for identifying anarc fault in a wire. The system includes a controller operably connectedto a first load via first wire; the controller configured to supply acurrent to the first load via the first wire, a first sense wireoperably connected to the first wire, the first sense wire operablyconnected to the controller. The controller includes a voltage sensefunction and a current sensing function, the controller operable toexecute a process to measure a first voltage on the first wire at thefirst load via the first sense wire, measure a second voltage on thefirst wire at a first output interface of the controller, and measure afirst current in the first wire. The controller is also configured toidentify any differences between the first voltage on the first wiremeasured at the first load and the second voltage on the first wiremeasure at the first output interface, ascertain any anomalies in thefirst current measured in the first wire, and correlate the differencesbetween the first voltage and the second with any anomalies in thecurrent to identify an arc fault.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include that thefirst sense wire is routed in parallel with the first wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include that thefirst sense wire is a shield associated with the first wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include that thefirst sense wire is routed with another wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include that thefirst sense wire is connected to the first wire in close proximity tothe first load.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include a secondsense wire operably connected to a second wire operably connected to asecond load, the second wire supplied by the controller, the secondsense wire in operable communication with the controller. The controlleris also operable to execute a method to measure a third voltage on thesecond wire at the load via the second sense wire, measure a fourthvoltage on the second wire at a second output interface of thecontroller, and measure a second current in the second wire. Thecontroller is also operable to execute a method to identify anydifferences between the third voltage on the second wire measured at theload and the fourth voltage on the second wire measured at the secondoutput interface, ascertain any anomalies in the second current measuredin the second wire, and correlate the differences between the thirdvoltage and the fourth voltage with any anomalies in the second currentto identify an arc fault.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include that thefirst load and the second load are the same.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include routing thefirst sense wire in parallel with the second wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include routing thesecond sense wire with the first wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include that thesecond sense wire is connected in close proximity to the second load.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include a third wireand a third sense wire, wherein the load is a three phase load.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that thecorrelating the differences between the first voltage and the secondwith any anomalies in the current to identify an arc fault in a wirefurther includes receiving a signal indicative of the envelope of thespectral content on the wire in a selected frequency range, receiving asignal indicative of current in the wire, applying a negative clippingfunction to the signal to form a positive envelope signal, and applyinga derivative function to the positive envelope signal, the derivativefunction yielding a pulse signal indicative of changes in the positiveenvelope signal. The correlating the difference between the firstvoltage and the second also includes that if the pulse signal exceeds afirst selected threshold, integrating the pulse signal to yield anaccumulated pulse signal; otherwise set the accumulated pulse signal tozero, if the accumulated pulse signal exceeds a second threshold set afirst flag as true indicating a selected amount of informationindicative of an arc fault has been acquired, counting the occurrenceswhen the first flag is set as true, and if the count exceeds a selectedthird threshold, set a second flag indicating the that the spectralcontent as measured from the wire indicates a possible series arc fault.The correlating the difference between the first voltage and the secondalso includes filtering the signal indicative of the current in the wireto formulate a pulse associated with when the measured current exhibitsan interruption, accumulating instances when the measured currentexhibits an interruption based on the pulses, and if the accumulatedinstances when the measured current exhibits an interruption exceeds afourth selected threshold and the a second flag indicating the that thespectral contend as measured from the wire indicates a possible seriesarc faults is set, then identify a series arc fault in the wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include thecontroller further operable to execute a method of identifying an arcfault in a wire further including that if the accumulated pulse signalexceeds a fifth selected threshold and the count exceeds a selectedsixth selected threshold, set a third flag indicating the that thespectral content as measured from the wire indicates a possible parallelarc fault, filtering the signal indicative of the current in the wire toformulate a pulse associated with when the measured current exhibits aninterruption, if the pulses exceed a seventh selected threshold,accumulating instances when the measured current exhibits aninterruption based on the pulses, if the accumulated instances when themeasured current exhibits an interruption exceeds an eighth selectedthreshold setting a fourth flag indicative of a current fault, and ifthe third flag indicating the that the spectral content as measured fromthe wire indicates a possible parallel arc fault is set and the fourthflag indicating a sufficient current fault is set, identify a parallelarc fault for the wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include thecontroller receiving a signal indicative of the envelope of the spectralcontent on the wire in a selected frequency range further includes avoltage sense function configured to measure a voltage on the firstwire, the controller operable to filter the first voltage on the firstwire with a bandpass filter having a selected pass band frequency rangeto select and retain spectral content, amplify the retained spectralcontent with a linear preamplifier, identify an envelope of theamplified retained spectral content by applying a logarithmic amplifierto the amplified retained spectral content, the envelope indicative ofthe RF energy content of the spectral content in the pass band of thevoltage on the first wire, a current sense function, the current sensefunction operable to measure a first current in the first wire, andcorrelating changes in the first current with a characteristic of theamplified retained spectral content to identify an arc fault, whereinthe characteristic includes a buffered envelope as a signal indicativeof the amount of energy in the selected passband frequency range.

Also described herein in yet another embodiment is a system foridentifying an arc fault in a wire, the system comprising a controlleroperably connected to a first load via first wire; the controllerconfigured to supply a current to the first load via the first wire,wherein the controller includes a voltage sense function configured tomeasure a voltage on the first wire, the controller operable to filterthe first voltage on the first wire with a bandpass filter having aselected pass band frequency range to select and retain spectralcontent, amplify the retained spectral content with a linearpreamplifier, and identify an envelope of the amplified retainedspectral content by applying a logarithmic amplifier to the amplifiedretained spectral content, the envelope indicative of the RF energycontent of the spectral content in the pass band of the voltage on thefirst wire. The controller also includes a current sense function, thecurrent sense function operable to measure a first current in the firstwire, correlating changes in the first current with a characteristic ofthe amplified retained spectral content to identify an arc fault,wherein the characteristic includes a buffered envelope as a signalindicative of the amount of energy in the selected passband frequencyrange.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include thecontroller operable to execute a method of identifying an arc fault in awire comprising, receiving a signal indicative of the envelope of thespectral content on the wire in a selected frequency range, receiving asignal indicative of current in the wire, applying a negative clippingfunction to the signal to form a positive envelope signal and applying aderivative function to the positive envelope signal, the derivativefunction yielding a pulse signal indicative of changes in the positiveenvelope signal. If the pulse signal exceeds a first selected threshold,integrating the pulse signal to yield an accumulated pulse signal;otherwise set the accumulated pulse signal to zero, and if theaccumulated pulse signal exceeds a second threshold set a first flag astrue. The system further includes the controller executing a method alsoincluding counting the occurrences when the first flag is set as true,if the count exceeds a selected third threshold, set a second flag,filtering the signal indicative of the current in the wire to formulatea pulse associated with when the measured current exhibits aninterruption, and accumulating instances when the measured currentexhibits an interruption based on the pulses. If the accumulatedinstances when the measured current exhibits an interruption exceeds afourth selected threshold and a second flag indicating the that thespectral contend as measured from the wire indicates a possible seriesarc faults is set, then identify a series arc fault in the wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include thecontroller further operable to execute a method of identifying an arcfault in a wire further including that if the accumulated pulse signalexceeds a fifth selected threshold and the count exceeds a selectedsixth selected threshold, set a third flag, filtering the signalindicative of the current in the wire to formulate a pulse associatedwith when the measured current exhibits an interruption, and if thepulses exceed a seventh selected threshold, accumulating instances whenthe measured current exhibits an interruption based on the pulses. Themethod further includes if the accumulated instances when the measuredcurrent exhibits an interruption exceeds an eighth selected thresholdsetting a fourth flag indicative of a current fault, and if the thirdflag indicating the that the spectral content as measured from the wireindicates a possible parallel arc fault is set and the fourth flagindicating a sufficient current fault is set, identify a parallel arcfault for the wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the system may include at least oneof the first selected threshold, the second selected threshold, thethird selected threshold, the fourth selected threshold, the fifthselected threshold, the sixth selected threshold, and the seventhselected threshold is based on empirical determination from test dataand selected to improve the detection and reduce nuisance trips.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that the passband is in the range of at least one of: about 10 MHz to about 40 MHz;about 10 MHz to about 80 MHz; and about 10 MHz to about 150 MHz.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that thenegative clipping function clipping function captures only increases inRF energy and avoid reductions to the envelope signal when no noise isdetected.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that settingthe first flag as true indicates a selected amount of informationindicative of an arc fault has been acquired.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that settingthe second flag as true indicates that the spectral content as measuredfrom the wire indicates a possible series arc fault.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that settingthe third flag as true indicates the that the spectral content asmeasured from the wire indicates a possible parallel arc fault.

Also described herein in yet another embodiment is a method foridentifying an arc characteristic in a wire operably connected between acontroller and a first load where the controller is configured to supplya current to the first load via the first wire and measure a voltage onthe first wire, the controller configured to execute a method, themethod including filtering the first voltage on the first wire with abandpass filter having a selected pass band to select and retainspectral content, wherein the pass band frequency range in the range ofabout 10 MHz to about 40 MHz, amplifying the retained spectral contentwith a linear preamplifier, and identifying an envelope of the amplifiedretained spectral content by applying a logarithmic amplifier to theamplified retained spectral content, the envelope indicative of the RFenergy content of the spectral content in the pass band. The method alsoincludes a current sense function, the current sense function includingmeasuring a first current in the first wire, and correlating changes inthe first current with a characteristic of the amplified retainedspectral content to identify an arc fault, wherein the characteristicincludes a buffered envelope as a signal indicative of the amount ofenergy in the selected pass band frequency range.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include thecontroller operable to execute a method of identifying an arc fault in awire including receiving a signal indicative of the envelope of thespectral content on the wire in a selected frequency range, receiving asignal indicative of current in the wire, applying a negative clippingfunction to the signal to form a positive envelope signal, and applyinga derivative function to the positive envelope signal, the derivativefunction yielding a pulse signal indicative of changes in the positiveenvelope signal. If the pulse signal exceeds a first selected threshold,integrating the pulse signal to yield an accumulated pulse signal;otherwise set the accumulated pulse signal to zero, if the accumulatedpulse signal exceeds a second threshold set a first flag as true. Inaddition, the method also includes counting the occurrences when thefirst flag is set as true, if the count exceeds a selected thirdthreshold, set a second flag as true, filtering the signal indicative ofthe current in the wire to formulate a pulse associated with when themeasured current exhibits an interruption, accumulating instances whenthe measured current exhibits an interruption based on the pulses, andif the accumulated instances when the measured current exhibits aninterruption exceeds a fourth selected threshold and the a second flagindicating the that the spectral contend as measured from the wireindicates a possible series arc faults is set, then identify a seriesarc fault in the wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include thecontroller further operable to execute a method of identifying an arcfault in a wire further including that if the accumulated pulse signalexceeds a fifth selected threshold and the count exceeds a selectedsixth selected threshold, set a third flag, filtering the signalindicative of the current in the wire to formulate a pulse associatedwith when the measured current exhibits an interruption, if the pulsesexceed a seventh selected threshold, accumulating instances when themeasured current exhibits an interruption based on the pulses, if theaccumulated instances when the measured current exhibits an interruptionexceeds an eighth selected threshold setting a fourth flag indicative ofa current fault, if the third flag indicating the that the spectralcontent as measured from the wire indicates a possible parallel arcfault is set and the fourth flag indicating a sufficient current faultis set, identify a parallel arc fault for the wire.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that at leastone of the first selected threshold, the second selected threshold, thethird selected threshold, the fourth selected threshold, the fifthselected threshold, the sixth selected threshold, and the seventhselected threshold is based on empirical determination from test dataand selected to improve the detection and reduce nuisance trips.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that the passband is in the range of at least one of: about 10 MHz to about 40 MHz;about 10 MHz to about 80 MHz; and about 10 MHz to about 150 MHz.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that thenegative clipping function clipping function captures only increases inRF energy and avoid reductions to the envelope signal when no noise isdetected.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that settingthe first flag as true indicates a selected amount of informationindicative of an arc fault has been acquired.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that settingthe second flag as true indicates that the spectral content as measuredfrom the wire indicates a possible series arc fault.

In addition to one or more of the features described above, or as analternative, further embodiments of the method may include that settingthe third flag as true indicates the that the spectral content asmeasured from the wire indicates a possible parallel arc fault.

Additional features and advantages are realized through the techniquesof the present disclosure. Other embodiments and aspects of thedisclosure are described in detail herein and are considered a part ofthe claimed disclosure. For a better understanding of the disclosurewith the advantages and the features, refer to the description.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the disclosure is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe disclosure are apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings in which:

FIG. 1 depicts a simplified diagram of an aircraft with an electricalsystem including various controllers and aircraft wiring in accordancewith an embodiment;

FIG. 2A depicts a partial diagram of a SSPC system depicting a portionof a controller interfaced with a load including sense wires inaccordance with an embodiment;

FIG. 2B depicts a partial diagram of a SSPC system depicting a portionof a controller interfaced with a load including sense wires inaccordance with an embodiment;

FIG. 2C depicts a partial diagram of a SSPC system depicting a portionof a controller interfaced with a load including sense wires inaccordance with an embodiment;

FIG. 2D depicts a partial diagram of a SSPC system depicting a portionof a controller interfaced with a load including sense wires inaccordance with an embodiment;

FIG. 2E depicts a partial diagram of a SSPC system depicting a portionof a controller interfaced with a load including sense wires inaccordance with an embodiment;

FIG. 3 depicts a simplified flowchart depicting the method ofidentifying an arc fault in a wire in accordance with an embodiment;

FIG. 4 depicts a partial diagram of a system for detecting an arc faultin a wire connected to a load in accordance with an embodiment;

FIG. 5A depicts a simplified flowchart depicting the method ofidentifying an series arc fault in a wire in accordance with anembodiment; and

FIG. 5B depicts a simplified flowchart depicting the method ofidentifying a parallel arc fault in a wire in accordance with anembodiment.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of this disclosure is thereby intended. The followingdescription is merely illustrative in nature and is not intended tolimit the present disclosure, its application or uses. It should beunderstood that throughout the drawings, corresponding referencenumerals indicate like or corresponding parts and features. As usedherein, the term controller refers to processing circuitry that mayinclude an application specific integrated circuit (ASIC), an electroniccircuit, an electronic processor (shared, dedicated, or group) andmemory that executes one or more software or firmware programs, acombinational logic circuit, and/or other suitable interfaces andcomponents that provide the described functionality.

Additionally, the term “exemplary” is used herein to mean “serving as anexample, instance or illustration.” Any embodiment or design describedherein as “exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments or designs. The terms “at least one”and “one or more” are understood to include any integer number greaterthan or equal to one, i.e. one, two, three, four, etc. The terms “aplurality” are understood to include any integer number greater than orequal to two, i.e. two, three, four, five, etc. The term “connection”can include an indirect “connection” and a direct “connection”.

In general, embodiments herein relate to an application of a method andsystem to identify series and parallel arc faults. Series and parallelarc faults generate a voltage across them that can be distinguished. Theexistence of an arc voltage is measured and used to validate theoccurrence of an arc fault event. To facilitate this measurement, in anembodiment, a sense wire/connection independent of the wire carryingpower to the load measures the arc voltage. The sense wire is routed outfrom the SSPC to the load in various ways but always referenced back tothe output of the SSPC. The sense wire can be a separate wire runningparallel to the wire under test, a separate wire running on a separatewire bundle and/or the shield of the wire under test, and the like. Inan SSPC application, a load sense wire is monitored for arc events bymeasuring the voltage drop across it. A difference of potential can bemeasured from the point the wire reaches the load and referenced back tothe output of the SSPC driving the load.

Advantageously, the described embodiments provide a clear indicationthrough arc voltage detection and looking for current variations as towhen a series arc fault or parallel arc fault is occurring. By routingthe sense wire along an alternate path as indicated in this invention,additional protection of the fault detection is provided.

Referring to FIG. 1, an aircraft 10 is shown. Aircraft 10 includes oneor more control systems shown generally as 12. The control system 12includes and interconnects with one or more controllers referred togenerally as 16 and more specifically as 16 l, 16 r commonly located ator near each engine 14 l, 14 r. Other controllers 16 such a Solid StatePower Controller (SSPC) 16 are also be depicted in this instance as 16a, 16 b, and the like.

In the described embodiments, the reference numerals are annotated withan “l” or “r” to denote the left or right side of the aircraft 10 forthe purpose of simplicity of description. Likewise, the annotation “a”,“b”, “n” is employed to simplify designation of a multiple enumerationof a component or element.

Each of the controllers 16 including engine controllers 16 r, 16 l andSSPC 16 a, 16 b are configured to receive various sensor signals fromsensors referred to generally as 18 and individually as 18 a, 18 b, . .. 18 n all over the aircraft 10 and may also operate one or moreactuators shown generally as 20, and more specifically as 20 a, 20 b, 20c, . . . 20 n to control the operation of the engines 14 r, 14 l, flightcontrols, (not shown), power systems, (not shown), and the like. Thecontrol system 12 may also be operably connected to various othercomponents throughout the aircraft 10, including, but not limited toother controllers 16, control panels 24, displays 26, and the like.

With reference to FIGS. 2A-2E, each depicting a partial block diagram ofa portion of an SSPC controller 16 in accordance with one or moreembodiments.

FIG. 2A depicts a portion of the SSPC 16 with an arc voltage sensecircuit 40, current sense circuit 50 and a sense wire 30 a operablyconnected thereto in accordance with an embodiment. In an embodiment,arc fault detection for the one or more controller(s) 16 is provided byvarious sense wires shown generally as 30, and more specifically as 30a, 30 b, 30 n and independent arc voltage sense circuits 40 in the SSPCcontroller(s) e.g. 16 and current sense circuits denoted as 50respectively, each integral with and connected to respective controllers16. In operation of an SSPC 16, a given load denoted as 60 a in thisinstance, is supplied with a power or a command signal on a selectedwire 62 a, also denoted as wire under test. The SSPC 16 may include aswitch or switching function as depicted by switch 64 that controls theapplication of the power or a command to the wire under test 62 a, whichis connected to the load 60 a. The sense wire, in this instance sensewire 30 a is operably connected to the wire under test 62 a in closeproximity to the load 60 a. The sense wire 30 a is also operablyconnected to the arc sense circuit 40. In this embodiment, the sensewire 30 a may be a shield on the wire under test 62 a.

In another embodiment, as depicted in FIG. 2B, the sense wire 30 b maybe a separate wire, routed essentially in parallel with the wire undertest 62 a.

In an embodiment, while switch 64 b is closed and the power or commandis provided to the load 60 a, the arc sense circuit 40 monitors thevoltage at the board interface output 66 of the SSPC 16 at the wireunder test 62 a. The arc sense circuit 40 also monitors the voltage onthe wire under test 62 a at the load 60 a via the sense wire 30 a. Thearc sense circuit 40 compares these two voltages and any difference involtage noted is identified as a potential arc fault. In addition, theSSPC 16 also includes a current sense circuit 50 for monitoring of thecurrent supplied by the SSPC 16 to the load 60. In an embodiment, theSSPC 16 monitors the current supplied to the load 60 as well. Currenttransients may be indicative of a fault. For example, increasing currenttransients may be indicative of a short circuit to ground or a shortcircuit to another circuit, while large decreasing current transientsare indicative of breaks in the wire under test 62 a. By correlating themeasured arc voltage measured differentials with the variations in thecurrent to the load 60 a, a more robust detection of arc faults isprovided.

FIG. 2C depicts embodiment of a portion of the SSPC 16 with arc voltagesense circuit 40, current sense circuit 50 and a sense wires 30 c inaccordance with another embodiment. Once again, in operation, of an SSPC16, a load 60 c is supplied with a power or a command signal on aselected wire, (e.g., wire under test) 62 c in this instance. In thisembodiment, second load 60 d is also supplied with a power or a commandsignal on a selected wire denoted 62 d, in this instance. That is,another power wire (and possibly a wire under test for another arcvoltage sense circuit 40). The SSPC 16, once again, may include switchor switching function 64 c, that controls the application of the poweror a command to the wire under test 62 c connected to the load 60 c. Thesense wire, in this instance sense wire 30 c is operably connected tothe wire under test 62 c in close proximity to the load 60 c and to thearc sense circuit 40 as described herein. In this embodiment, the sensewire 30 c is routed in close proximity to second power wire 62 d. Inthis manner, any fault likely to occur in the wire under test 62 c isunlikely to also affect the sense wire 30 c as it is routed in a harnesswith wire 62 d.

In this embodiment, once again while switch 64 c is closed and the poweror command is provided to the load 60 c, the arc sense circuit 40monitors the voltage at the board interface output 66 of the SSPC 16 andon the wire under test 62 c at the load 60 c via the sense wire 30 c.The arc sense circuit 40 compares these two voltages and any differencein voltage noted is identified as a potential arc fault as describedherein. In addition, the current sense circuit 50 monitors the currentsupplied by the SSPC 16 to the load 60 for current transients asdescribed herein. Once again, by correlating the measured arc voltagemeasured differentials with the variations in the current to the load 60c, a more robust detection of arc faults is provided.

FIG. 2D depicts another embodiment of a portion of the SSPC 16 fordetecting arc faults. In this embodiment, the SSPC 16 includes arcvoltage sense circuit(s) 40 e and 40 f, current sense circuit(s) 50 eand 50 f, and sense wire(s) 30 e and 30 f in accordance with anotherembodiment for a balanced load 60 e. In this embodiment, in operation,of an SSPC 16, the load 60 e is supplied with a power or a commandsignal on a selected wire, (e.g., wire under test) 62 e and a secondwire 62 f. That is, another power wire (and a second wire under test 62f for another arc voltage sense circuit denoted 40 f). The SSPC 16, onceagain, may include switch or switching function(s) 64 e, and 64 f thatcontrol the application of the power or a command to the wire under test62 e, and/or 62 f respectively. A first sense wire, in this instancesense wire 30 e is operably connected to the wire under test 62 e inclose proximity to the load 60 e and to the arc sense circuit 40 e asdescribed herein. In this embodiment, the sense wire 30 e is routed inclose proximity to second power wire 62 f. In this manner, any faultlikely to occur in the wire under test 62 e is unlikely to also affectthe sense wire 30 e as it is routed in a harness with wire 62 f.Similarly, a second sense wire, in this instance sense wire 30 f isoperably connected to the wire under test 62 e in close proximity to theload 60 e and to the arc sense circuit 40 f as described herein. In thisembodiment, the sense wire 30 f is routed in close proximity to firstpower wire i.e., wire under test 62 e. In this manner, any fault likelyto occur in the wire under test 62 f is unlikely to also affect thesense wire 30 f as it is routed in a harness with wire 62 e.

In this embodiment, once again while switch 64 e is closed and the poweror command is provided to the load 60 e, the arc sense circuit 40 emonitors the voltage at the board interface output 66 e of the SSPC 16at the wire under test 62 e. The arc sense circuit 40 e also monitorsthe voltage on the wire under test 62 e at the load 60 e via the sensewire 30 e. The arc sense circuit 40 compares these two voltages and anydifference in voltage noted is identified as a potential arc fault asdescribed herein. In addition, the current sense circuit 50 e monitorsthe current supplied by the SSPC 16 to the load 60 e for currenttransients as described herein. Once again, by correlating the measuredarc voltage measured differentials with the variations in the current tothe load 60 e, a more robust detection of arc faults is provided.Likewise, for the other half of the circuit, while switch 64 f is closedand the power or command is provided to the load 60 e via wire 64 f, thearc sense circuit 40 f monitors the voltage at the board interfaceoutput 66 f of the SSPC 16 at the wire under test 62 f. The arc sensecircuit 40 f also monitors the voltage on the wire under test 62 f atthe load 60 e via the sense wire 30 f. The arc sense circuit 40 fcompares these two voltages and any difference in voltage noted isidentified as a potential arc fault as described herein. In addition,the current sense circuit 50 f monitors the current supplied by the SSPC16 to the load 60 e for current transients as described herein. Onceagain, by correlating the measured arc voltage measured differentialswith the variations in the current to the load 60 e, a more robustdetection of arc faults is provided.

FIG. 2E depicts another embodiment of a portion of the SSPC 16 fordetecting arc faults for a three phase load. In this embodiment, theSSPC 16 includes arc voltage sense circuit(s) 40 g 40 h and 40 i,current sense circuit(s) 50 g, 50 h, and 50 i, and sense wire(s) 30 g,30 h, and 30 i in accordance with another embodiment for a three phaseload denoted 60 g. In this embodiment, in operation, of an SSPC 16, theload 60 g is supplied with a power or a command signal on a selectedwire, (e.g., wire under test) 62 g, a second wire 62 h, and a third wire62 i. That is, three wire(s) under test denoted 62 g, 62 h, and 62 irespectively for another arc voltage sense circuit denoted 40 g, 40 h,and 40 i respectively. The SSPC 16, once again, may include switch orswitching function(s) 64 g, 64 h, and 64 i that each respectivelycontrol the application of the power or a command to the wire(s) undertest 62 g, 62 h, and/or 62 i respectively.

A first sense wire, in this instance sense wire 30 g is operablyconnected to the wire under test 62 g in close proximity to the load 60e and to the arc sense circuit 40 g as described herein. In thisembodiment, the sense wire 30 g is routed in close proximity to a secondpower wire 62 h as described in the other embodiments herein. In thismanner, any fault likely to occur in the wire under test 62 g isunlikely to also affect the sense wire 30 g as it is routed in a harnesswith wire 62 h. Similarly, a second sense wire, in this instance sensewire 30 h is operably connected to the wire under test 62 h in closeproximity to the load 60 e and to the arc sense circuit 40 h asdescribed herein. In this embodiment, the sense wire 30 f is routed inclose proximity to a third power wire, i.e., wire under test 62 i. Inthis manner, any fault likely to occur in the wire under test 62 h isunlikely to also affect the sense wire 30 h as it is routed in a harnesswith wire 62 i.

Furthermore, in this embodiment, a third sense wire, in this instancesense wire 30 i is operably connected to the wire under test 62 i inclose proximity to the load 60 e and to the arc sense circuit 40 i asdescribed herein. In this embodiment, the sense wire 30 i is routed inclose proximity to the first power wire, i.e., wire under test 62 g. Inthis manner, any fault likely to occur in the wire under test 62 i isunlikely to also affect the sense wire 30 i as it is routed in a harnesswith wire 62 g. It should be appreciated that the sense wires could bethe shields or separates sense wires associated with the wires undertest 62 g, 62 h, 62 i routed with the wires under test 62 g, 62 h, 62 i.In addition, it should also be appreciated that the sense wires 30 g, 30h, 30 i could also be routed the another of the threes wires under test62 g, 62 h, and 62 i. For example, instead of the sense wire 30 g beingrouted with wire under test 62 h as described herein, it could insteadbe routed with wire under test 62 i. Likewise for the sense wires 62 hand 62 i each could be routed with a different wire under test thanidentified above.

In this embodiment, once again while the switch 64 g is closed and thepower or command is provided to the load 60 e, the arc sense circuit 40g monitors the voltage at the board interface output 66 g of the SSPC 16at the wire under test 62 g. The arc sense circuit 40 g also monitorsthe voltage on the wire under test 62 g at the load 60 g via the sensewire 30 g. The arc sense circuit 40 g compares these two voltages andany difference in voltage noted is identified as a potential arc faultas described herein. In addition, the current sense circuit 50 gmonitors the current supplied by the SSPC 16 to the load 60 g forcurrent transients as described herein. Once again, by correlating themeasured arc voltage measured differentials with the variations in thecurrent to the load 60 g, a more robust detection of arc faults isprovided. Likewise, for the second part of the circuit, while switch 64h is closed and the power or command is provided to the load 60 e viawire 62 h, the arc sense circuit 40 h monitors the voltage at thecontroller 16 board interface output 66 h of the SSPC 16 at the wireunder test 62 h. The arc sense circuit 40 h also monitors the voltage onthe wire under test 62 h at the load 60 g via the sense wire 30 h. Thearc sense circuit 40 h compares these two voltages and any difference involtage noted is identified as a potential arc fault as describedherein. In addition, the current sense circuit 50 h monitors the currentsupplied by the SSPC 16 to the load 60 g for current transients asdescribed herein. Once again, by correlating the measured arc voltagemeasured differentials with the variations in the current to the load 60g, a more robust detection of arc faults is provided. Finally, for thethird part of the circuit, while switch 64 i is closed and the power orcommand is provided to the load 60 e via wire 62 i, the arc sensecircuit 40 i monitors the voltage at the board interface output 66 i ofthe SSPC 16 at the wire under test 62 i. The arc sense circuit 40 h alsomonitors the voltage on the wire under test 62 i at the load 60 g viathe sense wire 30 i. The arc sense circuit 40 i compares these twovoltages and any difference in voltage noted is identified as apotential arc fault as described herein. In addition, the current sensecircuit 50 i monitors the current supplied by the SSPC 16 to the load 60g for current transients as described herein. Once again, by correlatingthe measured arc voltage measured differentials with the variations inthe current to the load 60 g, a more robust detection of arc faults isprovided. It should be appreciated that in a standard three-phase powerapplication, switches 64 g, 64 h, and 64 i would, as a matter ofpractice and implementation be opened or closed simultaneously, thoughit need not necessarily be the case.

FIG. 3 depicts a flowchart of a method 200 of detecting arc faults in acontrol system with a controller 16 supplying power or a control systemto a load 60 in accordance with an embodiment. The description on FIG. 3will refer, from time to time, to elements in FIGS. 1 and 2. Turning tothe method 200, the method 200 initiates at process block 205 where asense wire 30 is operably connected to a wire under test 62 in closeproximity to a load 60. At process step 210 the method 200 continueswith measuring a voltage on a wire under test 62 at the load 60 via thesense wire 30. The method also includes measuring a voltage on the wireunder test 62 at an interface output 66 to the controller 16 as depictedat process step 215. In addition, the method 200 includes measuring acurrent supplied to the load 60 as depicted at process step 220. Themethods 200 continues with identifying differences between the voltageon the wire under test 62 measured at the load 60 and the voltage on thewire under test 62 measured at the output interface 66 as depicted atprocess step 225. Furthermore, the method 200 also includes ascertainingany anomalies in the current measured in the wire under test 62 asdepicted at process step 230. Anomalies can include transients, largevariations spikes and the like. At process step 235, the method 200concludes with correlating any differences in the measured voltages withany current anomalies ascertained to identify an arc fault.

It should be appreciated that while previous methods have workedsatisfactorily for parallel arc fault detection (e.g., short to groundor another circuit), they and not very satisfactory for series arc faultdetection. Advantageously the described embodiments improve on priordetection techniques by coupling the differential voltage tests of thearc voltage sense circuit 40 with the measured current variations fromthe current sense circuit 50. Moreover, it should also be noted that theexisting methods associated with detecting current variations work lesseffectively as the line voltage increases (for example for 270 VDC powervs 28 VDC power). Finally, by routing the sense wire 30 a along analternate path as indicated in selected embodiments, additionalprotection of the fault detection is provided. Any fault will be lesslikely to affect the power wire, e.g. the wire under test 62 and sensewire 30 at the same time.

FIG. 4 depicts a simplified block diagram of another system and processas part of controller 16 for detecting arc faults in accordance with anembodiment. In an embodiment, the voltage on the wire under test 62 ismonitored by an arc fault sense circuit 40 as part of the controller 16.In an embodiment, the voltage is monitored at the controller outputinterface 66 as described herein.

Series and parallel arcs faults have been found to create radiofrequency (RF) noise over a wide spectral range of about 1 Mhz to 150Mhz, but in particular in the range of 10 Mhz to about 40 Mhz. Thedescribed embodiments of an arc fault detection circuit 40 employ afilter 42 feeding a one stage preamplifier 44 that then is directed toan RF detector 46 and finally to an output buffer 48. Then the output ofthis circuit is fed into the processor of the controller 16 formonitoring. In an embodiment, the filter 42 is an RF band pass filterwith a band pass range of about 10 MHz to 40 MHz, although other rangesare possible. The range is selected to correspond with the spectralcontent exhibited by the arc fault conducted on the wire under test 62.To facilitate monitoring and further processing the arc fault detectioncircuit 40 also includes a preamplifier 44 to amplify the filteredspectral content. In an embodiment, a standard RF amplifier may beemployed provided it exhibits sufficient operational bandwidth andlinearity. The preamplifier 44 may also contain a filter network to helpselect the appropriate frequency bands for monitoring. An RF Detectorcircuit 46 includes a standardized logarithmic amplifier 46 to furtheramplify the RF content gleaned from the measured voltage data from thewire under test 62 and glean additional information regarding the signalstrength in the frequency range of interest. The logarithmic amplifiersexhibits an output that represents a many-decade high dynamic range ofhigh-frequency input signal amplitudes by a relatively narrow outputrange signal, thereby correlating to the “energy” in the high frequencycontent of the information in band pass range. This information is thenbuffered by a buffer amplifier 48 and then provided to themicroprocessor of the controller 16 for processing in accordance withone or more detections methods.

In the microprocessor additional software logic may be used to look forspecific time domain characteristics of the arc such as length of timefor detected noise and repeating patterns. The described embodimentsprovide a clear indication through RF detection as to when a series arcfault or parallel arc fault is occurring. In one embodiment, when theoutput of the detection circuit 40 exceeds a selected threshold, it isconstrued as the presence of an arc fault. In another embodiment, theoutput of the arc fault detection circuit 40 can be correlated with thedetected transients from the current sense circuit 50 to identify thepresence of an arc fault with improved accuracy and reliability whencompared to existing techniques. It should also be noted thatadvantageously, the described embodiments do not depend on current droopon series arc faults and are more immune to the effects of highervoltages as it directly detects the signature noise from the arc itself.In addition, the detection circuit is small and low cost and readilyimplemented in a hardware preprocessing configuration.

FIG. 5A depicts another flowchart of a method 500 of detecting arcfaults in a control system with a controller 16 supplying power orcontrol signals to a load 60 via a wire under test 62 in accordance withan embodiment. The description on FIG. 5 will refer, from time to time,to elements in FIGS. 1-4. The various constants and filter timeconstants for both FIGS. 5a and 5b are empirically derivedexperimentally by looking at the characteristics of captured test datafor currents and RF energy and their waveforms. For example, the‘integrate above threshold value’ is selected to ignore low level noisefrom the circuit and from A/D sampling.

The method 500 initiates with system and processes described withrespect to FIG. 4 and identifying the relevant RF content and currentsensing. In this embodiment, the method 500 initiates at process block505 with receiving, by the processor of the controller 16 signalsindicative of relevant RF measurements and spectral content from thewire under test 62 (e.g. the output 49 of buffer amplifier 48 (FIG. 4)).Similarly, the process 500 also includes receiving a signal indicativeof the current measurements from the current sensing circuit 50 (FIG. 4)as described herein at process step 510. At process step 515 the method500 continues with a negative clipping function. The negative clippingfunction is configured to simplify further processing by limiting thesign of the spectral content envelope signals from the RF detectorcircuit 46 (FIG. 4) to positive values. The negative clipping functioncaptures only increases in RF energy and ensures avoiding inadvertentlydecaying the result of the following accumulation during times when nonoise is detected, which, in turn, ensures that the accumulationintegrator to have the right decay time constant. The method 500continues at process step 520 with applying a filter derivative toidentify changes in the RF content of the process voltage from the wireunder test 62. The derivative identifies the changes in the originalspectral content and in particular, whether the frequency band ofinterest (10 Mhz to 50 Mhz) has had a significant positive change inamplitude. This feature captures the changing amplitude of noise thatoccurs during a typical arcing process and differentiates it fromconstant background noise. At process step 525, the changes that areidentified by the derivative function at process step 520 are integratedabove a selected threshold. The integration establishes and accumulatesdifference pulses above an established selected threshold. The thresholddefines a limit for circuit sampling DC noise at the A/D thus onlydetecting significant RF content changes in the integration. Continuingwith FIG. 5 and the method 500, at process step 530, the resultingpulses that exceed another selected threshold are evaluated, flagged andcounted as shown at process step 535. If the count of flags (pulses thatexceeded the threshold) accumulates such that it exceeds anotherselected threshold, it is indicative of the spectral content from the RFdetection 42 (FIG. 4) as depicted at process step 540 meeting selectedcharacteristics indicative of an arc fault.

Continuing with FIG. 5A and the current sense branch of the flow chart,the current in the wire under test 62 as measured by the current sensecircuit 50 is received at block 510. This measured current is receivedat process step 545, which provides a high frequency filtering functionthat formulates a pulse for instances where the measured currentexhibits partial dropouts. That is, in instances where measuredtransient breaks in the current delivered to the wire under test 62. Atprocess step 550 the pulses are integrated to establish pulsesindicative of the instances of the current drop outs. Finally, turningto process block 555, if the flag from process step 540 is setindicating the presence of the selected RF signature on the wire undertest 62 exceeding the selected threshold, and the cumulative pulses fromprocess block 550 exceed a selected threshold, indicating that thesensed current is indicative of a potential fault, then a series arcfault is indicated by process block 555.

Turning to FIG. 5B and the description of the method 500 continues withthe process steps for detecting parallel arc faults. The method 500continues at process blocks 560 with receiving the integrated,accumulated pulses and the pulse count from process steps 525 and 535respectively indicative of relevant RF measurements and spectral contentfrom the wire under test 62. If the value of the integrated, accumulatedpulses exceeds a selected threshold and the pulse count from processstep 535 exceeds another selected threshold, then a true flag is setindicating a potential arc fault condition has been detected. Meanwhile,at process step 570, the current received from the current sense circuit50 is differentiated and then subsequently integrated to accumulate allinstances of current transients. Once again, as depicted at process step575, if the accumulated instances of current transients exceeds aselected threshold a true flag is set for the current tests. Finally,turning to process block 580 if the flag from process step 560 is setindicating the presence of the selected RF signature on the wire undertest 62 exceeding the selected threshold, and the cumulative pulses fromprocess block 575 exceed a selected threshold, indicating that thesensed current is indicative of a potential fault, then a parallel arcfault is indicated.

It should be appreciated that the methodologies described with respectto FIGS. 5A and 5B may readily be applied to the embodiments employingsense wires ad described herein. In those instances, the processing maybe part of the correlation between the voltage measured in the sensewires and the current in the wire under test. Furthermore, it shouldfurther be appreciated that various embodiments as described herein maybe combined in whole or in part with other embodiments to facilitatevarious implementations for detecting and identifying both series andparallel arc faults. It should also be appreciated, that each of theselected thresholds may be selected based on actual measurements ofvarious arc configurations and selected to “optimize” the detection andminimize nuisance tripping based on false positive determinations. Itshould also be appreciated that in the described embodiments, thisoptimization is accomplished to center the results between the pointwhere excess noise would be picked up and the point where the actual arcwould not be detected. The various constants and filter time constantsmay empirically derived experimentally based on the characteristics ofcaptured test data for measured voltages on the sense wires or wiresunder test as well as the currents and RF energy and their waveforms.For example, the ‘integrate above threshold value’ is selected to ignorelow level noise from the circuit and from A/D sampling employed in theprocessing. In another example, the filter derivative time constant isselected to allow closely spaced RF pulses to be later counted togetherbut to filter out pulses that are spaced widely apart. Likewise, thepulse detect is selected as a threshold to see adequate RF energy toconsider it a true pulse.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of onemore other features, integers, steps, operations, element components,and/or groups thereof. For the purposes of this disclosure, it isfurther understood that the terms “inboard” and “outboard” can be usedinterchangeably, unless context dictates otherwise.

The present embodiments may be a system, a method, and/or a computerprogram product at any possible technical detail level of integration.The computer program product may include a computer readable storagemedium (or media) having computer readable program instructions thereonfor causing a processor to carry out aspects of the present disclosure.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments. In this regard, each block in the flowchart or blockdiagrams may represent a module, segment, or portion of instructions,which comprises one or more executable instructions for implementing thespecified logical function(s). In some alternative implementations, thefunctions noted in the blocks may occur out of the order noted in theFigures. For example, two blocks shown in succession may, in fact, beexecuted substantially concurrently, or the blocks may sometimes beexecuted in the reverse order, depending upon the functionalityinvolved. It will also be noted, that each block of the block diagramsand/or flowchart illustration, and combinations of blocks in the blockdiagrams and/or flowchart illustration, can be implemented by specialpurpose hardware-based systems that perform the specified functions oracts or carry out combinations of special purpose hardware and computerinstructions.

While the present disclosure has been described in detail in connectionwith only a limited number of embodiments, it should be readilyunderstood that the present disclosure is not limited to such disclosedembodiments. Rather, the present disclosure can be modified toincorporate any number of variations, alterations, substitutions,combinations, sub-combinations, or equivalent arrangements notheretofore described, but which are commensurate with the scope of thepresent disclosure. Additionally, while various embodiments of thepresent disclosure have been described, it is to be understood thataspects of the present disclosure may include only some of the describedembodiments.

What is claimed is:
 1. A system for identifying an arc fault in a wire,the system comprising: a controller operably connected to a first loadvia first wire; the controller configured to supply a current to thefirst load via the first wire; wherein the controller includes a voltagesense function configured to measure a voltage on the first wire, thecontroller operable to: filter the first voltage on the first wire witha bandpass filter having a selected pass band frequency range to selectand retain spectral content; amplify the retained spectral content witha linear preamplifier; identify an envelope of the amplified retainedspectral content by applying a logarithmic amplifier to the amplifiedretained spectral content, the envelope indicative of the RF energycontent of the spectral content in the pass band of the voltage on thefirst wire; wherein the controller incudes a current sense function, thecurrent sense function operable to measure a first current in the firstwire; correlating changes in the first current with a characteristic ofthe amplified retained spectral content to identify an arc fault,wherein the characteristic includes a buffered envelope as a signalindicative of the amount of energy in the selected passband frequencyrange; wherein the controller is further operable to execute a method ofidentifying an arc fault in the first wire comprising: receiving asignal indicative of the envelope of the spectral content on the firstwire in a selected frequency range; receiving a signal indicative ofcurrent in the first wire; applying a negative clipping function to thesignal to form a positive envelope signal; applying a derivativefunction to the positive envelope signal, the derivative functionyielding a pulse signal indicative of changes in the positive envelopesignal; if the pulse signal exceeds a first selected threshold,integrating the pulse signal to yield an accumulated pulse signal;otherwise set the accumulated pulse signal to zero; if the accumulatedpulse signal exceeds a second threshold set a first flag as true;counting the occurrences when the first flag is set as true; if thecount exceeds a selected third threshold, set a second flag; filteringthe signal indicative of the current in the wire to formulate a pulseassociated with when the measured current exhibits an interruption;accumulating instances when the measured current exhibits aninterruption based on the pulses; and if the accumulated instances whenthe measured current exhibits an interruption exceeds a fourth selectedthreshold and a second flag indicating the that the spectral contend asmeasured from the wire indicates a possible series arc faults is set,then identify a series arc fault in the first wire; wherein setting thefirst flag as true indicates a selected amount of information indicativeof an arc fault has been acquired.
 2. The system for identifying an arcfault as recited in claim 1, wherein the controller is further operableto execute a method of identifying an arc fault in the first wirefurther comprising: if the accumulated pulse signal exceeds a fifthselected threshold and the count exceeds a selected sixth selectedthreshold, set a third flag; filtering the signal indicative of thecurrent in the wire to formulate a pulse associated with when themeasured current exhibits an interruption; if the pulses exceed aseventh selected threshold, accumulating instances when the measuredcurrent exhibits an interruption based on the pulses; if the accumulatedinstances when the measured current exhibits an interruption exceeds aneighth selected threshold setting a fourth flag indicative of a currentfault; if the third flag indicating the that the spectral content asmeasured from the wire indicates a possible parallel arc fault is setand the fourth flag indicating a sufficient current fault is set,identify a parallel arc fault for the wire.
 3. The system foridentifying an arc fault as recited in claim 2, wherein at least one ofthe first selected threshold, the second selected threshold, the thirdselected threshold, the fourth selected threshold, the fifth selectedthreshold, the sixth selected threshold, and the seventh selectedthreshold is based on empirical determination from test data andselected to improve the detection and reduce nuisance trips.
 4. Thesystem for identifying an arc fault as recited in claim 2, whereinsetting the third flag as true indicates the that the spectral contentas measured from the first wire indicates a possible parallel arc fault.5. The system for identifying an arc fault as recited in claim 1,wherein the pass band is in the range of at least one of: about 10 MHzto about 40 MHz; about 10 MHz to about 80 MHz; and about 10 MHz to about150 MHz.
 6. The system for identifying an arc fault as recited in claim1, wherein the negative clipping function captures only increases in RFenergy and avoid reductions to the envelope signal when no noise isdetected.
 7. The system for identifying an arc fault as recited in claim1, wherein setting the second flag as true indicates that the spectralcontent as measured from the first wire indicates a possible series arcfault.
 8. A method for identifying an arc characteristic in a wireoperably connected between a controller and a first load where thecontroller is configured to supply a current to the first load via thefirst wire and measure a voltage on the first wire, the controllerconfigured to execute a method, the method comprising: filtering thefirst voltage on the first wire with a bandpass filter having a selectedpass band to select and retain spectral content, wherein the pass bandfrequency range in the range of about 10 MHz to about 40 MHz; amplifyingthe retained spectral content with a linear preamplifier; identifying anenvelope of the amplified retained spectral content by applying alogarithmic amplifier to the amplified retained spectral content, theenvelope indicative of the RF energy content of the spectral content inthe pass band; wherein the controller incudes a current sense function,the current sense function including measuring a first current in thefirst wire; correlating changes in the first current with acharacteristic of the amplified retained spectral content to identify anarc fault, wherein the characteristic includes a buffered envelope as asignal indicative of the amount of energy in the selected pass bandfrequency range; wherein the controller is further operable to execute amethod of identifying an arc fault in the first wire comprising:receiving a signal indicative of the envelope of the spectral content onthe first wire in a selected frequency range; receiving a signalindicative of current in the first wire; applying a negative clippingfunction to the signal to form a positive envelope signal; applying aderivative function to the positive envelope signal, the derivativefunction yielding a pulse signal indicative of changes in the positiveenvelope signal; if the pulse signal exceeds a first selected threshold,integrating the pulse signal to yield an accumulated pulse signal;otherwise set the accumulated pulse signal to zero; if the accumulatedpulse signal exceeds a second threshold set a first flag as true;counting the occurrences when the first flag is set as true; if thecount exceeds a selected third threshold, set a second flag as true;filtering the signal indicative of the current in the wire to formulatea pulse associated with when the measured current exhibits aninterruption; accumulating instances when the measured current exhibitsan interruption based on the pulses; and if the accumulated instanceswhen the measured current exhibits an interruption exceeds a fourthselected threshold and a second flag indicating the that the spectralcontend as measured from the first wire indicates a possible series arcfaults is set, then identify a series arc fault in the first wire;wherein the negative clipping function captures only increases in RFenergy and avoid reductions to the envelope signal when no noise isdetected.
 9. The method for identifying an arc fault as recited in claim8, wherein the pass band is in the range of at least one of: about 10MHz to about 40 MHz; about 10 MHz to about 80 MHz; and about 10 MHz toabout 150 MHz.
 10. The method for identifying an arc fault as recited inclaim 8, wherein setting the first flag as true indicates a selectedamount of information indicative of an arc fault has been acquired. 11.The method for identifying an arc fault as recited in claim 8, whereinsetting the second flag as true indicates that the spectral content asmeasured from the first wire indicates a possible series arc fault. 12.A method for identifying an arc characteristic in a wire operablyconnected between a controller and a first load where the controller isconfigured to supply a current to the first load via a first wire andmeasure a voltage on the first wire, the controller configured toexecute a method, the method comprising: filtering the first voltage onthe first wire with a bandpass filter having a selected pass band toselect and retain spectral content, wherein the pass band frequencyrange in the range of about 10 MHz to about 40 MHz; amplifying theretained spectral content with a linear preamplifier; identifying anenvelope of the amplified retained spectral content by applying alogarithmic amplifier to the amplified retained spectral content, theenvelope indicative of the RF energy content of the spectral content inthe pass band; wherein the controller incudes a current sense function,the current sense function including measuring a first current in thefirst wire; correlating changes in the first current with acharacteristic of the amplified retained spectral content to identify anarc fault, wherein the characteristic includes a buffered envelope as asignal indicative of the amount of energy in the selected pass bandfrequency range; wherein the controller is further operable to execute amethod of identifying an arc fault in the first wire comprising:receiving a signal indicative of the envelope of the spectral content onthe first wire in a selected frequency range; receiving a signalindicative of current in the first wire; applying a negative clippingfunction to the signal to form a positive envelope signal; applying aderivative function to the positive envelope signal, the derivativefunction yielding a pulse signal indicative of changes in the positiveenvelope signal; if the pulse signal exceeds a first selected threshold,integrating the pulse signal to yield an accumulated pulse signal;otherwise set the accumulated pulse signal to zero; if the accumulatedpulse signal exceeds a second threshold set a first flag as true;counting the occurrences when the first flag is set as true; if thecount exceeds a selected third threshold, set a second flag as true;filtering the signal indicative of the current in the first wire toformulate a pulse associated with when the measured current exhibits aninterruption; accumulating instances when the measured current exhibitsan interruption based on the pulses; and if the accumulated instanceswhen the measured current exhibits an interruption exceeds a fourthselected threshold and a second flag indicating the that the spectralcontend as measured from the first wire indicates a possible series arcfaults is set, then identify a series arc fault in the first wire; ifthe accumulated pulse signal exceeds a fifth selected threshold and thecount exceeds a selected sixth selected threshold, set a third flag;filtering the signal indicative of the current in the first wire toformulate a pulse associated with when the measured current exhibits aninterruption; if the pulses exceed a seventh selected threshold,accumulating instances when the measured current exhibits aninterruption based on the pulses; if the accumulated instances when themeasured current exhibits an interruption exceeds an eighth selectedthreshold setting a fourth flag indicative of a current fault; if thethird flag indicating the that the spectral content as measured from thefirst wire indicates a possible parallel arc fault is set and the fourthflag indicating a sufficient current fault is set, identify a parallelarc fault for the first wire.
 13. The method for identifying an arcfault as recited in claim 12, wherein at least one of the first selectedthreshold, the second selected threshold, the third selected threshold,the fourth selected threshold, the fifth selected threshold, the sixthselected threshold, and the seventh selected threshold is based onempirical determination from test data and selected to improve thedetection and reduce nuisance trips.
 14. The method for identifying anarc fault as recited in claim 12, wherein setting the third flag as trueindicates the that the spectral content as measured from the first wireindicates a possible parallel arc fault.